74 BOTANICAL GAZETTE [JULY 
of such plains grasses as Bulbilis and Bouteloua. No cacti of any kind 
are found, although they are present in mountain parks at slightly lower 
altitudes. The large proportion of Papilionaceae and Carduaceae here 
noted is to be expected in any area of the Rocky Mountain region. 
Many of the plants are recorded from all of the minor communities 
in the list; some from only a part. The species here noted include most 
of the common ones of xerophytic areas of higher parks, but only about 
one-half of the entire number of species in the dry grassland of Boulder 
Park. 
The figures in the list are for percentages of ground covered. 
Amounts less than one-tenth of 1 per cent are given as o.1 per cent. 
An asterisk (*) is placed after the names of species found in all or all 
but one of the different communities. 
The water requirements of the several species will be understood 
best if the reader will keep in mind that the most xerophytic plant 
assemblage is represented in column 1, and that the other columns 
represent in order less and less arid conditions. Hencea plant shown only 
at the left of the table is hyperxerophytic, as Poa rupicola and Allium 
recurvatum. One recorded chiefly at the right is hypoxerophytic, as 
Agrostis hiemalis and Stipa viridula. It should be mentioned, however, 
that an occasional stray may get in anywhere, as Thermopsis divari- 
carpa, a meadow plant here recorded from the driest situation.— 
Francis RAMALEY, University of Colorado, Boulder, Colo. 
